Thursday 6 March 2014 04.00 EST
First published on Thursday 6 March 2014 04.00 EST

Setting up the terms of her polemic against the fashion industry, Tansy Hoskins defines fashion in utilitarian terms as "changing styles of dress and appearance adopted by groups of people", and the industry as one in which there is "a shrinking distinction between high fashion and high street fashion". She does acknowledge that the whole business is both "glorious and enthralling, as well as exasperating and terrible", though she doesn't come close to conveying its appeal as well as Diana Vreeland once did: "Fashion must be the most intoxicating release from the banality of the world."

As fashion editor of Harper's Bazaar and then as editor of Vogue, Vreeland was once the ultimate fashion insider. Hoskins is an interested outsider, determined to change minds. So even though her intention is to show us what Karl Lagerfeld has to do with Karl Marx, she never represents fashion as the sigh of the soul in a soulless world. Stitched Up instead disapproves of the idea of fashion itself. And for good reasons: it focuses on the social consequences of the industry, from the conditions of workers to its disastrous environmental costs, collecting a number of useful, at times horrifying, facts in one place.

It is nearly a year since 1,133 garment workers died and 2,500 were injured in Bangladesh, when a poorly constructed factory collapsed just north-west of the capital, Dhaka. The discovery of the labels of western manufacturers in the rubble highlighted long supply chains and the practice of subcontracting at every stage. Amid the shocked reactions, some of the retailers could plausibly claim that they had no idea their clothes were made at Rana Plaza, or about the state of a building they didn't know existed. What happened in Bangladesh is a perfect starting point for Hoskins's attack, but she hasn't set out only to condemn the consumers of cheap fashion; she wants to show how the entire system is a trick to divert attention from how clothes are made, who actually wears them, and who makes all the money.

She goes for the high end. So while her book reminds us that Stefan Persson, the owner of H&M, bought a whole village in Hampshire in 2009, it dwells on the luxury conglomerates, the richest and most ruthless of which is LVMH (Louis Vuitton/Moët Hennessy), an intricate nest of companies that includes among its brands Christian Dior, Louis Vuitton and Céline. In the course of her convincing denial of the possibility of "ethical fashion", Hoskins tells the story of Edun, the clothing line started by Ali Hewson and her husband Bono. It began with the intention of manufacturing in sub-Saharan Africa, but after a poor initial reception, LVMH bought a 49% stake in the company in 2010 and immediately moved 85% of its manufacturing out of Africa – mainly to China.

At the other end of the scale, LVMH lost patience with Christian Lacroix, selling the house in 2005. The couturier filed for bankruptcy in 2009 and (like a select club of designers, such as Martin Margiela and Jil Sander) no longer has the rights to his own name. As Hoskins says a little gleefully he "now designs interiors and uniforms for train companies and collaborates with high‑street chains".

In 2012, Johann Rupert, the CEO of the much smaller Richemont (owner of Chloé and Dunhill) said: "I feel like I'm having a black-tie dinner on top of a volcano." Western luxury brands are very worried about China, in particular what will happen when a Chinese label becomes as prestigious as, say, Givenchy. Ever‑resourceful LVMH has been buying Indian brands, and in 2012 bought a stake in the Trendy International Group, a Chinese company specialising in casual wear. So for the time being at least, there is no immediate threat to the dominance of the brands who show in New York, Milan, London and Paris – especially given the way they are structured: 55% of Chanel's profits, for example, come from perfume and cosmetics. But change will inevitably come.

Hoskins is quite clear that high-end fashion is guilty of covering up a system of imitation and exploitation under the guise of novelty – so that a catwalk collection is immediately ripped off and copied by a mass-market retailer, and made up in a factory in Dhaka in appalling conditions. She is good on the question of "size zero", on advertising and on racism, too. Is Fashion Racist? asks one chapter heading. Of course it is. Hoskins reminds us of the Navajo nation suing Urban Outfitters, in a case that is still to be settled, for using its name on a range of products in 2012. Urban Outfitters' response was to argue that the tribe's federal trademark registration should be cancelled. She could also have reminded us of Dolce and Gabbana's "blackamoor" earrings for its spring 2013 collection, a surprising revival of an art deco jewellery fad. And Vogue India's "Slum Dwellers" shoot in 2008.

Stitched Up explores and analyses the existing industry, but also has another aim. The final three chapters – Resisting Fashion, Reforming Fashion and Revolutionising Fashion – take on a strangely programmatic tone, which can best be conveyed by the final chapter, in which Hoskins "imagines a post-capitalist society where capitalism has been overthrown and the world is in a state of permanent revolution". This reads rather like a pamphlet written by Central Committee. Perhaps it is enough to say that the garment industry ws vividly how the capitalist system works, and that labour is anything but immaterial in parts of the world where "our" clothes are made.

The great value of Stitched Up as polemic lies in its reminder that while very few of us can take the blame for the deaths of the three crocodiles needed to make an exclusive handbag (if you're tempted, there's a grim description), it is harder to absolve ourselves from other crimes of the global industry – from, for instance, the squandering of water to irrigate cotton crops that has led to the disappearance of the Aral Sea in Uzbekistan. The fashion industry is sizeist, it's racist, it's exploitative. Yet will it ever be overthrown? Do people want it to be? Even when its veils are stripped away, as they are in this book, we still so easily succumb to fashion's glamour and its fantasies of self-transformation. As Vreeland said: "I think fantasists are the only realists in the world. The world is a fantasy. Nothing's remarkably real."